“Comparison of the effectiveness of the combination therapy of ondansetrone-dexamethasone to granisetrone-dexamethasone in the preventing of acute nausea - vomiting due to TAC regimen of chemotherapy in breast cancer patients” Cut Mela Yunita Sari, M. Riswan, Fauzi Yusuf Division of Medical Hematology and Oncology, Departement of Internal Medicine Faculty of Medicine, University of Syiah Kuala / Dr. Zainoel Abidin General Hospital Banda AcehIndonesia Background. The American Cancer Society estimates that in 2013 , there were 14 % of all cancer deaths caused by breast cancer . TAC regimen of chemotherapy is one of treatment modality of breast cancer , and has a high emetic potential. Ondansetron and granisetron plays an important role in the prevention of acute nausea and vomiting due to chemotherapy. Ondansetron as an effective single dose in 32mg doses, while effective at a dose of 1mg granisetron. Purpose. To obtain a comparison between the effectiveness of the combination therapy of ondansetronedexamethasone to granisetrone – dexamethasone in the preventing of acute nausea - vomiting due to TAC regimen of chemotherapy in breast cancer patients. Patients and Methods. This study is a clinical trial with single-blind and cross-over design , the first group received ondansetron 32mg and dexamethasone 20mg on the first cycle and then got granisetron 1mg and dexamethasone 20 mg on the second cycle or vice versa in the second group . This research was conducted at Dr.Zainoel Abidin’s Hospital from June to August 2013 . All subjects performed an assessment of the quality of nausea , vomiting frequency , therapeutic response and side effects within the first 24 hours of chemotherapy. Results. There was no significant difference in the degree of nausea , vomiting and frequency response between combination therapy with ondansetrone – dexamethasone to granisetrone- dexamethasone in the prevention of acute nausea and vomiting due to TAC regimen. The most common side effects reported were decreased appetite, headache, abdominal discomfort, insomnia and impaired vision. Side effects more visual disturbances reported in ondansetron group, p = 0.02. Conclusion. Granisetron - dexamethasone combination therapy has the same effectiveness with ondansetron -dexamethasone , both well tolerated , although side effects were reported more visual impairment in the ondansetron group. Keywords : Antiemetics, breast cancer, chemotherapy, dexamethasone, graniisetrone, ondansetrone, TAC regimen,